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We develop a 1-D atmospheric photochemistry model for Mars to interpret hydrogen chloride (HCl) profile measurements collected by the ACS MIR spectrometer aboard the ExoMars Trace Gas Orbiter (TGO) in Mars Year (MY) 34. We include a gas-phase chlorine chemistry scheme and study 1) surface chemistry, 2) hydrolysis, 3) photolysis, and 4) hydration and photolysis of dust grains as possible sources of gas-phase chlorine chemistry. Heterogeneous uptake of chlorine species onto water ice and minerals in Martian dust are loss processes common to all mechanisms. We drive the 1-D model using TGO profile measurements of aerosols and water vapour. We find that mechanism four can reproduce observed HCl profile tendencies during MY34. It reproduces the HCl cut-off at high southern latitudes (

Carbon monoxide is a non-condensable gas in the Martian atmosphere produced by the photolysis of CO2. Its abundance responds to the condensation and sublimation of CO2 from the polar caps, resulting in seasonal variations of the CO mixing ratio. ACS onboard the ExoMars Trace Gas Orbiter have measured CO in infrared bands by solar occultation. Here we provide the first long-term monitoring of the CO vertical distribution at the altitude range from 0 to 80 km for 1.5 Martian years from Ls = 163° of MY34 to the end of MY35. We obtained a mean CO mixing ratio of ∼960 ppmv at latitudes from 45°S to 45°N and altitudes below 40 km, mostly consistent with previous observations. We found a strong enrichment of CO near the surface at Ls = 100–200° in high southern latitudes with a layer of 3,000–4,000 ppmv, corresponding to local depletion of CO2. At equinoxes we found an increase of the CO mixing ratio above 50 km to 3,000–4,000 ppmv at high latitudes of both hemispheres explained by the downwelling flux of the Hadley circulation on Mars, which drags the CO enriched air. General circulation models tend to overestimate the intensity of this process, bringing too much CO. The observed minimum of CO in the high and mid-latitudes southern summer atmosphere amounts to 700–750 ppmv, agreeing with nadir measurements. During the global dust storm of MY34, when the H2O abundance peaks, we see less CO than during the calm MY35, suggesting an impact of HOx chemistry on the CO abundance.

A wide-field zenith-looking telescope operating in a mode similar to Time-Delay-Integration (TDI) or drift scan imaging can perform an infrared sky survey without active pointing control but it requires a high-speed, low-noise infrared detector. Operating from a hosted payload platform on the International Space Station (ISS), the Emu space telescope employs the paradigm-changing properties of the Leonardo SAPHIRA electron avalanche photodiode array to provide powerful new observations of cool stars at the critical water absorption wavelength (1.4 $\mu$m) largely inaccessible to ground-based telescopes due to the Earth's own atmosphere. Cool stars, especially those of spectral-type M, are important probes across contemporary astrophysics, from the formation history of the Galaxy to the formation of rocky exoplanets. Main sequence M-dwarf stars are the most abundant stars in the Galaxy and evolved M-giant stars are some of the most distant stars that can be individually observed. The Emu sky survey will deliver critical stellar properties of these cool stars by inferring oxygen abundances via measurement of the water absorption band strength at 1.4 $\mu$m. Here we present the TDI-like imaging capability of Emu mission, its science objectives, instrument details and simulation results., Comment: Accepted for publication in Journal of Astronomical Telescopes, Instruments, and Systems (JATIS)

This article takes an approach to creating a machine learning model for the oil and gas industry. This task is dedicated to the most up-to-date issues of machine learning and artificial intelligence. One of the goals of this research was to build a model to predict the possible risks arising in the process of drilling wells. Drilling of wells for oil and gas production is a highly complex and expensive part of reservoir development. Thus, together with injury prevention, there is a goal to save cost expenditures on downtime and repair of drilling equipment. Nowadays, companies have begun to look for ways to improve the efficiency of drilling and minimize non-production time with the help of new technologies. To support decisions in a narrow time frame, it is valuable to have an early warning system. Such a decision support system will help an engineer to intervene in the drilling process and prevent high expenses of unproductive time and equipment repair due to a problem. This work describes a comparison of machine learning algorithms for anomaly detection during well drilling. In particular, machine learning algorithms will make it possible to make decisions when determining the geometry of the grid of wells—the nature of the relative position of production and injection wells at the production facility. Development systems are most often subdivided into the following: placement of wells along a symmetric grid, and placement of wells along a non-symmetric grid (mainly in rows). The tested models classify drilling problems based on historical data from previously drilled wells. To validate anomaly detection algorithms, we used historical logs of drilling problems for 67 wells at a large brownfield in Siberia, Russia. Wells with problems were selected and analyzed. It should be noted that out of the 67 wells, 20 wells were drilled without expenses for unproductive time. The experiential results illustrate that a model based on gradient boosting can classify the complications in the drilling process better than other models.

International audience; Carbon monoxide (CO) is the main product of CO2 photolysis in the Martian atmosphere. Production of CO is balanced by its loss reaction with OH, which recycles CO into CO2. CO is therefore a sensitive tracer of the OH-catalysed chemistry that contributes to the stability of CO2 in the atmosphere of Mars. To date, CO has been measured only in terms of vertically integrated column abundances, and the upper atmosphere, where CO is produced, is largely unconstrained by observations. Here we report verti- cal profiles of CO from 10 to 120 km, and from a broad range of latitudes, inferred from the Atmospheric Chemistry Suite on board the ExoMars Trace Gas Orbiter. At solar longitudes 164–190°, we observe an equatorial CO mixing ratio of ~1,000 ppmv (10–80 km), increasing towards the polar regions to more than 3,000 ppmv under the influence of downward transport of CO from the upper atmosphere, providing a view of the Hadley cell circulation at Mars’s equinox. Observations also cover the 2018 global dust storm, during which we observe a prominent depletion in the CO mixing ratio up to 100 km. This is indicative of increased CO oxidation in a context of unusually large high-altitude water vapour, boosting OH abundance.

We report retrievals in the 2.53 – 2.79 μm spectral range using the Atmopheric Chemistry Suite onboard of ExoMars Trace Gas Orbiter, which allow the simultaneous measurement of vertical profiles of H and O isotope ratios in water vapour in the Martian atmosphere. The large coverage of ACS MIR solar occultations provides the possibility to analyse the spatial, seasonal and diurnal variations of these ratios. 1. Introduction Isotopic ratios in C, O and H provide important clues to understand the history and evolution of volatiles on Mars. Enrichment of the D/H ratio by a factor of approximately 5.5 in atmospheric water vapour with respect to the Vienna Standard Mean Ocean Water [1] has often been understood as evidence of the substantial atmospheric escape into space. On the other hand, oxygen isotope ratios in both water vapour and carbon dioxide do not show substantial enrichment of the heavier isotopes (e.g. [2],[3]). The lack of substantial fractionation therefore indicates the presence of a large reservoir of oxygen to exchange with the atmosphere [4]. In this work, we use solar occultation measurements made with the mid-infrared (MIR) channel of the Atmospheric Chemistry Suite (ACS), onboard ExoMars Trace Gas Orbiter (TGO) to measure the evolution of the vertical structure of the isotopic composition of water vapour (D/H, 18O/16O and 17O/16O) at the terminator for a full Martian year. 2. Measurements ACS consists of a set of three infrared spectrometers covering a total wavelength range from 0.7 to 17 μm. The MIR channel, used in this study, is a cross-dispersion echelle spectrometer dedicated to solar occultation measurements in the 2.3-4.2 μm (2300-4400 cm-1) range, with the main objective of measuring high resolution spectra (λ/Δλ∼30000-50000) in a wide instantaneous spectral range (width 0.15-0.3 μm). In order to cover the full spectral range, MIR is equipped with a steerable secondary grating that allows the selection of different diffraction orders [5]. In this work, we analyse MIR spectra in secondary grating positions 4 and 5, which allow the simultaneous measurement of several diffraction orders covering a spectral range from 2.67 to 2.79 μm (3584-3745 cm-1) and 2.53 to 2.67 μm (3745-3952 cm-1), respectively. We select spectral windows in several diffraction orders, which show absorption lines of the four main oxygen isotopologues of water vapour (H216O, H218O, H217O, HD16O) and CO2 (see Figure 1). Figure 1: Example of one ACS MIR spectral window in diffraction order 224, measured at tangent heights of 19, 35 and 50 km. The black dots represent the measured spectra, and the green line shows the best fit to the data. The contribution from each species to the spectra is also shown, following the colours in the legend. 3. Radiative Transfer Analysis The analysis of the spectra is performed using the NEMESIS code [6], which works under the optimal estimation framework. In particular, for each solar occultation, we retrieve simultaneous vertical profiles of pressure, temperature and volume mixing ratio of the four main water isotopologues. The pressure and temperature profiles can be constrained from the CO2 absorption lines under the assumption of hydrostatic equilibrium and a given CO2 volume mixing ratio profile, which we obtain from the Mars Climate Database [7]. In the case of the water vapour isotopologues, the volume mixing ratios can be constrained from the depth of the corresponding absorption lines, which are observed up to 60 km approximately. The retrieval scheme is applied to all ACS MIR observations made with secondary grating positions 4 and 5 for a full Martian year, covering a wide range of latitudes, seasons, and local time, and enabling, for the first time, the study of the climatology of both the O and H isotopic ratios in Martian water vapour. 4. Summary and Conclusions Vertical profiles of the isotope ratios in the four main water vapour isotopologues (D/H, 18O/16O and 17O/16O) at the terminator are obtained using solar occultation measurements by the Atmospheric Chemistry Suite onboard ExoMars Trace Gas Orbiter. The large coverage of ACS solar occultation measurements allows, for the first time, the analysis of the variations of the O and H isotopic composition of water vapour for a full Martian year. References [1] Owen, T., Maillard, J. P., de Bergh, C., and Lutz, B. L..: Deuterium on Mars: The abundance of HDO and the values of D/H, Science, 240, 1767 LP - 1767, 1988. [2] Webster, C. R., Mahaffy, P. R., Flesch, G. J., Niles, P. B., Jones, J. H., Leshin, L. A., Atreya, S. K., Stern, J. C., Chrsitensen, L. E., Owen, T., Franz, H., Pepin, R. O., and Steele, A.: Isotope Ratios of H, C and O in CO2 and H2O of the Martian Atmosphere, Science, 341, 260 LP – 263, 2013. [3] Krasnopolsky, V.A., Maillard, J. P., Owen, T., Toth, R. A., Smith, M. D.: Oxygen and carbon isotope ratios in the martian atmosphere, Icarus, Vol. 192, Issue 2, 2007. [4] Jakosky, B. M.: Mars Volatile Evolution: Evidence from Stable Isotopes, Icarus, 94, 14-31, 1991. [5] Korablev et al.: The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter, Space Science Reviews, vol. 214, pag. 7, 2017. [6] Irwin, P., Teanby, N., de Kok, R., Fletcher, L., Howett, C., Tsang, C., Wilson, C., Calcutt, S., Nixon, C., Parrish, P.: The NEMESIS planetary atmosphere radiative transfer and retrieval tool, Journal of Quantitative Spectroscopy and Radiative Transfer,109, 1136-1150. [7] Forget, F., Hourdin, F., Fournier, R., Hourdin, C., Talagrand, O., Collins, M., Lewis, S. R., Read, P. L., and Huot, J-P: Improved general circulation models of the Martian atmosphere from the surface to above 80 km, Journal of Geophysical Research: Planets, 104, 24155-24175, 1999.

ESA’s ExoMars program comprises two missions including the Trace Gas Orbiter (TGO), launched in 2016, and a rover and surface platform, to be launched in 2022. The main scientific objectives of the program are to investigate the Martian environment and climate and search for past or present signs of life. For this purpose, a suite of three infrared spectrometers for remote sensing (Atmospheric Chemistry Suite, ACS) is in use on TGO. One of these instruments is a Fourier transform spectrometer, TIRVIM (Thermal IR V-shape Interferometer Mounting in honor of Vassili Ivanovich Moroz), operating in nadir, limb or solar occultation mode between 1.7 and 17 μm. On ExoMars22’s surface platform the spectrometer FAST (Fourier for Atmospheric Species and Temperature) will study the atmosphere and surface at the landing site in the same wavelength range as TIRVIM on TGO. This paper presents the objectives of TIRVIM and FAST. It summarizes selected results of the determination of temperature profiles and dust content in the lower atmosphere of Mars based on radiative transfer modeling of TIRVIM data. Synergetic analyses of TIRVIM spectra and InSight (NASA) in situ measurements of temperature and pressure at InSight’s landing site in Elysium Planitia enable improvements of procedures to retrieve parameters from TIRVIM observations. First results on surface temperature obtained from these different data sets together with the measurements to be expected in the future from FAST offer a unique opportunity to compare in situ and IR remote sensing measurements.

Water reaches Mars' upper atmosphere Mars once hosted abundant water on its surface but subsequently lost most of it to space. Small amounts of water vapor are still present in the atmosphere, which can escape if they reach sufficiently high altitudes. Fedorova et al. used data from the ExoMars Trace Gas Orbiter spacecraft to determine the distribution of water in Mars' atmosphere and investigate how it varies over seasons. Water vapor is sometimes heavily saturated, and its distribution is affected by the planet's large dust storms. Water can efficiently reach the upper atmosphere when Mars is in the warmest part of its orbit, and this behavior may have controlled the overall rate at which Mars lost its water. Science , this issue p. 297

International audience; The properties of Martian aerosols are an integral part of the planetary climatology. Global dust storms (GDS) significantly alter spatial and vertical distributions of dust and water ice aerosols and their microphysical properties. We explored the 2018/Martian Year 34 GDS with the Atmospheric Chemistry Suite (ACS) instrument onboard the ESA‐Roscosmos Trace Gas Orbiter (TGO) mission. Solar occultation observations of Thermal InfraRed (TIRVIM) and Near InfraRed (NIR) channels in the 0.7−6 μm spectral range with >103 signal‐to‐noise ratio are used to constrain the vertical dependence and the temporal evolution of the particle properties of water ice and dust (effective radius, effective variances, number density, and mass loading) before the 2018 GDS and during its onset and decay phases. In most of the observations, the particle size of dust and water ice decreases with altitude. The effective radius of dust and water ice particles ranges from 0.1−3.5 μm and 0.1−5.5 μm, respectively. The largest aerosol particles (> 2.5 μm for dust and > 3.5 μm for water ice) are present below 10 km before the onset and during the GDS decay phase. During the peak of the GDS, dust reached altitudes of 85 km; the most frequently observed effective radius is 1−2 μm with 0.1−1 cm‐3 number density and 0.1 effective variance. Detached layers of water ice composed of 0.1−1 μm particles are systematically observed at 50−100 km during this period. Below, at 0−50 km, we see the dust mixed with the main water ice layer comprising 1−4 μm particles.

Oxygen isotope ratios provide important constraints on the history of the Martian volatile system, revealing the impact of several processes that might fractionate them, such as atmospheric loss into space or interaction with the surface. We report infrared measurements of the Martian atmosphere obtained with the mid-infrared channel (MIR) of the Atmospheric Chemistry Suite (ACS), onboard the ExoMars Trace Gas Orbiter. Absorption lines of the three main oxygen isotopologues of water vapour (H216O, H218O, and H217O) observed in the transmission spectra allow, for the first time, the measurement of vertical profiles of the 18O/16O and 17O/16O ratios in atmospheric water vapour. The observed ratios are enriched with respect to Earth-like values (δ18O = 200 ± 80‰ and δ17O = 230 ± 110‰ corresponding to the Vienna Standard Mean Ocean Water). The vertical structure of these ratios does not appear to show significant evidence of altitudinal variations.

An interferometer is an essential subsystem of the Fourier-transform spectrometer (FTS). We describe an FTS instrument to operate at the surface of Mars based on a Michelson interferometer with hollow retroreflectors. The instrument will operate in two different regimes, observing the solar disc through the atmosphere to measure trace gases, and measuring the thermal emission from the atmosphere to study the planetary boundary layer (PBL). The interferometer has an aperture of 1 inch, operates in the spectral range 1.7-17 μm, and features low mass and volume (≤1 kg with all necessary subsystems). Beam splitter and compensator are made of potassium bromide (KBr). A single-axis robot with stepper motor drive provides a linear movement of the retroreflector (the speed stability is about 2%) and enables a maximal optical path difference (MOPD) of 15 cm. A reference channel with a distributed-feedback laser diode (0.76 μm) and a photodiode (Si) supports the interferogram sampling and the speed stabilization loop. The time to measure one interferogram with a best spectral resolution of about 0.05 cm–1 is 500 s (the sun tracking regime). In the thermal sounding regime, one measurement of a two-side interferogram (with the spectral resolution of ~1 cm–1) takes less than 1 min. Laboratory calibrations with a black body and a laser confirm the design parameters of the instrument.

Atmospheric Chemistry Suite (ACS) is a part of Russian contribution to ExoMars Trace Gas Orbiter (TGO) ESA-Roscosmos mission. ACS includes three separate infrared spectrometers (MIR, NIR and TIRVIM) with a different spectral coverage and targeted to the different science goals. ACS TIRVIM is a Fourier-transform spectrometer based on 2-inch double pendulum interferometer. It operates in the spectral range of 1.7-7 μm with the best spectral resolution 0.13 cm-1 for solar occultation (SO) mode and 0.8 cm-1 for nadir mode. In nadir mode TIRVIM is purposed to thermal sounding of the Martian atmosphere and aerosol properties retrieval. In SO mode TIRVIM is dedicated to trace gases measurements complementing to ACS MIR. After successful launch of ExoMars TGO on 16 April 2016 there were three time slots for turning on science instruments during cruise phase to execute necessary checks and calibration measurements. In March 2018 the nominal science orbit was reached after cruise and aerobraking phases. The first results of TIRVIM data processing show high performance of the instrument.

We discuss the results of measurements made with the Planetary Fourier Spectrometer (PFS) onboard the Mars Express spacecraft. The data were obtained in the beginning of the mission and correspond to the end of summer in the southern hemisphere of Mars (L s ∼ 340°). Three orbits are considered, two of which passed through volcanoes Olympus and Ascraeus Mons (the height above the surface is about +20 km), while the third orbit intersects lowland Hellas (−7 km). The influence of the relief on the properties of the aerosol observed is demonstrated: clouds of water ice with a visual optical thickness of 0.1–0.5 were observed above volcanoes, while only dust was found during the observations (close in time) along the orbit passing through Hellas in low and middle latitudes. This dust is homogeneously mixed with gas and has a reduced optical thickness of 0.25±0.05 (at v = 1100 cm−1). In addition to orographic clouds, ice clouds were observed in this season in the northern polar region. The clouds seen in the images obtained simultaneously by the mapping spectrometer OMEGA confirm the PFS results. Temperature inversion is discovered in the north polar hood below the level 1 mbar with a temperature maximum at about 0.6 mbar. This inversion is associated with descending movements in the Hadley cell.

International audience; The acousto-optic spectrometer of the near infrared range, which is a part of the spectrometer SPICAM onboard the Mars-Express spacecraft, began to operate in the orbit of Mars in January 2004. In the SPICAM experiment, a spectrometer on the basis of an acousto-optic filter was used for the first time to investigate other planets. During one and a half years of operation, the IR channel of SPICAM obtained more than half a million spectra in the 1-1.7 μm range with a resolving power of more than 1500 in different modes of observation: limb, nadir, and solar eclipses. The main goal of the experiment is to study the content of water vapor in the Martian atmosphere by measuring the absorption spectrum in the 1.38 μm band. Characteristics of the instrument (high spectral resolution and signal-to-noise ratio) allow one to solve a number of additional scientific problems including the study of ozone distribution by emission of singlet oxygen (O2 1Δg), detection of the water and carbonic dioxide ices, and also the study of the vertical distribution and optical characteristics of aerosol in the Martian atmosphere. We present a description of the instrument, the results of its ground and in-flight calibrations, and a brief survey of the basic scientific results obtained by the SPICAM spectrometer during a year-and-half of operation.

International audience; The SPICAM Light optical package on the ESA Mars Express mission is dedicated to the nadir and limb observations in the UV between 118 nm and 320 nm, and has originally included an IR solar occultation channel, an inheritance of the IR part of the SPICAM solar occultation instrument for Mars 96. Because of severe mass constrains of the mission this channel has been replaced by a lightweight (0.7 kg) near infrared instrument that employs a new technology acousto-optical tuneable filter (AOTF). This channel is dedicated to the nadir measurements of water vapour column abundance in the near infrared between 1 and 1.7 μm simultaneously with ozone measured in the UV. In addition to the measurements of water vapour column abundance in the band of 1.38 μm, the NIR nadir spectrometer will measure the CO2 quantity in the bands of 1.43, 1.57-1.6 μm, and, consequently, the surface pressure (with known topography); and will contribute to the studies of atmospheric aerosols and the surface, by spectro-polarimetry measurements. Fully functional model of the instrument has been assembled, has been undergone a number of tests; the spectra of terrestrial atmospheric transmittance have been recorded. The scientific context of the experiment will be discussed along with the instrument's description; current development status and the calibration results will be presented.